CALGARY, Alberta, May 24 (Reuters) - A strike at CanadianPacific Railway Ltd is unlikely to drag on long enoughto prompt a return to bargain-basement price discounts forCanadian crude oil, growing volumes of which is moving to marketby train as pipelines run nearly full.

In addition, far greater volumes move on trains from NorthDakota's booming Bakken shale oil region, where the carrier'sworkers remain on the job, another factor that should prevent aprice collapse, at least for awhile, analysts said.

Canadian Labour Minister Lisa Raitt said the governmentcould legislate employees back to work as early as Monday. TheConservative government of Prime Minister Stephen Harper hasbeen quick to step in to halt work stoppages involving transportcompanies, citing the potential to harm the economy.

While railroads including CP Rail and Canadian NationalRailway Co still move a relatively small portion ofCanada's roughly 3 million barrels a day of oil output, theyhave provided a release valve as efforts to boost the capacityof major pipelines run into regulatory and political obstacles.

So far, the CP Rail dispute has not affected pricedifferentials for key crude types derived from the Alberta oilsands such as light synthetic and Western Canada Select heavy, atrade source said.

"CP would have to be out for weeks for it to take anyeffect," the source said.

The strike began in the normally slow trading period forCanadian crude in the last week of the month before business forJuly deliveries will begin in earnest.

WCS for July was discussed in a range of $18 to $18.75 abarrel under benchmark West Texas Intermediate, according toShorcan Energy Brokers, down about $2.50 from June businessquoted. During the winter, the spread widened to beyond $35under WTI. July synthetic was bid at $4.50 a barrel under WTI.

"I expect that there will be little or no impact ondifferentials as most of the crude volumes that matter todifferentials are being moved on the U.S. side of the border,which is not affected by the strike," said Martin King, analystwith FirstEnergy Capital Corp.

In a report, Wells Fargo Securities analysts said Bakkenproducers in North Dakota are not directly exposed to the CPRail dispute but cautioned that pipeline capacity could tightenincrementally if the dispute drags on.

In addition, Wells Cargo said a prolonged walkout couldaffect the WCS spread due to what it termed "CP's leadingposition in the Alberta oil sands."

On Wednesday, Crescent Point Energy, one of thelargest oil producers in Saskatchewan, said it normally movesabout 8,000 barrels a day by rail, a volume that has increasedsince loading facilities were installed about half a year ago.

It sees only a minimal impact on its operations, especiallygiven expectations for Ottawa to step in and end the walkout.

A second Saskatchewan oil producer, Cenovus Energy Inc, said it was forced to seek pipeline space for about2,000 bpd and was confident it would find it.